Effects of funnel web spider toxin on Ca2+ currents in neurohypophysial terminals. Academic Article uri icon

Overview

abstract

  • Funnel web spider toxin (FTX) is reportedly a specific blocker of P-type Ca2+ channels. The effects of FTX on the Ca2+ currents of isolated neurohypophysial nerve terminals of the rat were investigated using the 'whole-cell' patch-clamp technique. Both the transient and long-lasting Ca2+ current components were maximally elicited by depolarization from a holding potential equal to the normal terminal resting potential (-90 mV). Externally applied FTX inhibited the high-voltage-threshold, transient component of the Ca2+ current in a concentration-dependent manner, with a half-maximal inhibition at a dilution of approximately 1:10000. FTX also shifted the peak current of the I-V relationship by +10 mV. The long-lasting Ca2+ current component, which is sensitive to L-type Ca2+ channel blockers, was insensitive to FTX. The transient current, which is sensitive to omega-conotoxin GVIA, was completely blocked by FTX. These results suggest that there could be a novel, inactivating Ca2+ channel in the rat neurohypophysial terminals which is affected by both N-type and P-type Ca2+ channel blockers.

publication date

  • November 14, 1994

Research

keywords

  • Benzylisoquinolines
  • Calcium Channel Blockers
  • Nerve Endings
  • Pituitary Gland, Posterior
  • Polyamines
  • Spider Venoms

Identity

Scopus Document Identifier

  • 0028151506

Digital Object Identifier (DOI)

  • 10.1016/0006-8993(94)91266-1

PubMed ID

  • 7874504

Additional Document Info

volume

  • 663

issue

  • 2